Unless otherwise indicated herein, the description in this section is not prior art to the claims in this application and is not admitted to be prior art by inclusion in this section.
An image forming apparatus such as a copier, a facsimile, and a multi-functional peripheral forms an image on a sheet (recording medium) during conveying. These sheets are available in various types, and sheets different in, for example, material, surface property, and thickness are used. Thus, while a satisfactory image formation quality may be obtained due to using a specific-type sheet, an image formation quality may deteriorate due to using the other-type sheet. For example, when an image formation is performed on a sheet having large unevenness on its surface under an image formation condition optimized for a sheet having a little unevenness on its surface, a recording material moves into concave portions. This consequently and becomes prone to exposure of the sheet surface at which the recording material should present.
To solve this type of problem, a configuration where a user specifies a sheet type to be used in advance is widely employed. However, a low-quality printed matter is often output because the user forgets to specify a sheet type. Thus, an image forming apparatus having a function of detecting a sheet type is proposed.
For example, one print apparatus is proposed. This print apparatus includes: a sensor unit including a light emitting element irradiating a paper sheet, and a detecting element receiving a light reflected by a surface of the paper sheet, and determines, for example, a surface shape of the paper sheet and a resolution from a detection signal of the detecting element.
Additionally, another image forming apparatus is proposed. This print apparatus includes a paper thickness detection roller located in, for example, a sheet conveying path, and identifies a paper sheet thickness from a displacement amount of the paper thickness detection roller pushed up by a paper sheet passing via immediately below the paper thickness detection roller.